Rh conflict during pregnancy: causes, treatment or observation?

Pregnancy is a rather complex process, the course of which determines the life of the child, the mother, and their health. One of the most important components of the proper course of pregnancy is the Rh factor.

In order to understand which Rh factor the expectant mother has, a special test for alloimmune antibodies is carried out. It allows you to determine whether there is a special protein in the blood located on the surface of red blood cells. If it is not there, then the person has negative Rh blood (it occurs in 15% of the world's inhabitants). In everyday life it doesn’t bother us at all, but when carrying a child, everything changes, as it can cause many problems. For example, it can cause Rhesus conflict. Rhesus conflict is the interaction of negative and positive blood particles (erythrocytes), as a result of which they stick together (agglutination) and disturbances appear.

Causes of Rhesus conflict

Rhesus - a conflict arises only when a woman’s body already has antibodies that negatively affect the normal development of the child. Antibodies can begin to be produced in the fetus and mother only in the middle or end of pregnancy. If the mother’s antibodies begin to penetrate through the bloodstream to the child and attack red blood cells, we are talking about a Rhesus conflict.

When pregnancy proceeds normally, and the blood flow of the mother and fetus does not interact at all, then there will be no threat to the child

Rhesus – conflict can still arise in the following situations:

if bleeding occurred during childbirth, and the mother’s blood came into contact with the baby’s blood (in this case, during the first birth there will be no danger for the baby, but during the second there may be a great risk, because the process of producing antibodies has already started). This situation occurs in 10–15% of all cases; the risk increases significantly with caesarean section;
miscarriage that occurred more than 6 weeks;
the occurrence of injuries during pregnancy often leads to trauma to the blood vessels of the fetus and placenta, as a result of which blood can mix and the production of antibodies occurs, which destroy the fetal red blood cells;
in some situations, the production of antibodies may begin before pregnancy (for example, if Rh-positive blood was mistakenly transfused during a blood transfusion);
ectopic pregnancy or abortion. Medical abortions are responsible for 6% of cases of antibody development, ectopic pregnancy – 1% of cases.

Once this process has been started, the antibodies will be constantly present. But at the same time, if the Rhesus conflict manifested itself during the first pregnancy, this may happen, then it will not negatively affect the fetus, because the immune system has only just begun to produce antibodies.

Features of pregnancy management in Rh-negative women

When managing pregnancy in women with Rh-negative blood, it is necessary to determine the titer of anti-Rhesus antibodies monthly. In their absence, at 28 weeks of pregnancy, rhesus conflict is prevented by administering anti-rhesus immunoglobulin .

The second stage of prevention is carried out in the early postpartum period (within 72 hours after birth), if a positive Rh factor is detected in the newborn.

Prescription of anti-Rhesus immunoglobulin to Rh-negative women in the absence of antibodies in their blood is necessary after carrying out procedures accompanied by the danger of blood getting from the child to the mother:

artificial termination of pregnancy or spontaneous miscarriage;
ectopic pregnancy;
invasive diagnostics;
bleeding during pregnancy;
closed abdominal injury of a pregnant woman;
external rotation of the fetus during breech presentation.

All women with Rh-negative blood should be aware of the need for prophylactic use of anti-Rh immunoglobulin in the first 72 hours after childbirth, abortion, miscarriage, and ectopic pregnancy from an Rh-positive partner.

Symptoms of Rhesus conflict

In fact, it is quite difficult to immediately understand that there is a rhesus conflict. Some women may experience symptoms similar to gestosis (the baby’s body spends a lot of energy creating more and more new red blood cells).

You can find out if there is a Rhesus conflict with the help of special tests and ultrasound examination. They can show:

condition of the fetal organs: have the kidneys, liver, heart, spleen increased in size;
is there swelling of the placenta, which causes thickening of the umbilical cord and enlargement of the placenta;
whether swelling of the fetus has occurred, or there is an accumulation of fluid in the chest or abdominal cavity;
are there any changes in the child’s position (he takes the “Buddha” pose, when the legs move to the sides through the enlarged abdomen and chest);
whether swelling of the soft tissues of the brain has occurred, which leads to a bifurcation of the contour of the head.

The manifestation of such symptoms can cause fetal death as early as 20-30 weeks of development. If a child is born, he is usually found to have anemia or jaundice. In more severe cases, serious damage to important organs may occur (body weight increases by 1.5 times, which is very dangerous for newborns and can cause death).

Possible complications from Rhesus conflict

The most important issue for the mother is the consequences that can await the child after the occurrence of Rhesus conflict. Some of the most dangerous consequences are oxygen starvation of the brain, as well as the accumulation of fluid in all cavities and organs of the baby. As a result, the normal functioning of all systems is disrupted, and edema, which is very dangerous for the child, may appear. In this case, only intensive therapy can help the baby, since without treatment, it is unlikely that the child will be saved.

Also, pregnancy with Rhesus conflict causes the following complications:

anemia;
premature birth;
bleeding;
gestosis;
miscarriage;
complications after pregnancy.

It is worth noting that fetal death is possible only in the case of a complex Rhesus conflict; in other cases, the consequences may not be so tragic, but they should not be underestimated.

Relationship between blood groups of children and parents

So, what is the relationship between the blood type of parents and children, does it exist at all? There really is such a relationship; the blood type, like any other trait, is passed on to the child from the parents, but it does not always have to be the same. A person's blood type is inherited according to one of the basic laws in genetics, Mendel's law. Gregor Johann Mendel is an Austrian scientist, biologist, founder of the doctrine of inheritance. The laws of inheritance of monogenic traits that he discovered form the basis of modern genetics. A person’s blood type is one of many such monogenic characteristics, which is formed as a result of a random combination of genes from the mother and father of the unborn baby.

Blood groups

It is customary to distinguish four human blood groups according to the ABO system, depending on the presence of antigens A and B.

The first group does not contain antigens, that is, it is designated OO.
The second group contains the A antigen and is designated AO.
The third group contains the B antigen and is designated BO.
The fourth group contains both antigens and is designated AB accordingly.

The child inherits one antigen from each parent; accordingly, the child’s blood type will depend on the resulting combination.

Dynamic control and diagnostics

To predict how the pregnancy will develop, it is important that the woman comes for a consultation as early as possible (this is especially true if this is the second or third pregnancy), and she has previously been diagnosed with antibody sensitization or hemolytic disease of the newborn/fetus.

To control the progress of pregnancy it is important:

during registration, all pregnant women must undergo laboratory tests such as determining their blood group and Rh factor;
if a woman is found to be Rh negative, the father is also recommended to undergo the test;
if the fears are confirmed and the parents have different Rh factors, then the pregnant woman is tested for the presence of antibody titres every 8 days until the 20th week;
determine the type of immunoglobulins (IgG or IgM);
after 20 weeks, the pregnant woman is sent for observation to a specialized center;
from 32 weeks, antibody titer tests are done once every 14 days, and from 35 weeks - once every 7 days;
The situation can be predicted by the gestational age in which antibodies were detected. It will be the more unfavorable, the earlier immunoglobulins to the Rh factor were discovered.

If antibodies are detected during the second pregnancy, the occurrence of Rh conflict increases, so invasive or non-invasive treatment methods cannot be avoided.

Rhesus conflict during pregnancy

In accordance with the definition, Rh immunization (Rh sensitization/Rh conflict) is the appearance of Rh antibodies in a pregnant woman in response to fetal erythrocyte antigens entering the bloodstream, i.e., to paraphrase more simply, this is the incompatibility of a mother with a Rh-negative blood group with a child who has Rh positive blood group (and not with my husband, as many people think).

Rh antigen is a protein found in the membrane of most people's red blood cells/erythrocytes. The blood of such people is Rh positive, and the blood of those who do not have this protein is called Rh negative. About 1/3 of the population is Rh negative.

Rh-positive parents may well have a Rh-negative child. In this case, a very peaceful, conflict-free relationship develops between the “positive” mother and her “negative” child: such a combination poses no threat to either the woman or the fetus.

If the mother and father of the child have a Rh negative blood group, the child also has a negative Rh factor.

But if the mother has Rh-negative blood and the father has positive blood, a Rh-positive fetus occurs in 60% of pregnant women, but incompatibility develops in only 1.5% of these pregnancies.

As a rule, with a second pregnancy the likelihood of incompatibility is higher than with the first.

The mechanism of development of Rh conflict

If Rh-positive red blood cells meet Rh-negative ones, they stick together - agglutination. To prevent this from happening, the immune system of a Rh-negative mother produces special proteins - antibodies, which combine with the Rh protein in the membrane of the fetal red blood cells (antigens), preventing them from sticking to the mother's own red blood cells. Antibodies are called immunoglobulins and come in two types: IgM and IgG.

Contact of fetal red blood cells with antibodies occurs in the space between the wall of the uterus and the placenta. When fetal Rh-positive red blood cells first encounter the immune system of the Rh-negative mother, IgM is produced, the size of which is too large to penetrate the placental barrier. That is why, as a rule, during the first pregnancy of an Rh-negative mother with an Rh-positive fetus, conflict arises relatively rarely. Incompatibility develops when fetal antigens (Rh positive red blood cells) re-enter the bloodstream of the Rh-negative mother, whose immune system in this case massively produces IgG, which, being smaller in size, penetrate the placenta and cause hemolysis, i.e. destruction of fetal red blood cells. This is how hemolytic disease of the fetus/newborn develops.

Complications of Rhesus conflict

As a result of the destruction of red blood cells, toxic damage occurs to almost all organs and systems of the fetus as a result of the breakdown of hemoglobin, a substance contained in red blood cells and responsible for oxygen transport. This occurs due to the breakdown product - bilirubin. First of all, the central nervous system of the fetus, liver, kidneys and heart are affected; fluid accumulates in its cavities and tissues, which interferes with the normal functioning of organs and systems, including intrauterine death in severe cases. It is in connection with this “rejection” of the fetus that Rh-negative mothers often develop the threat of miscarriage, and the risk of intrauterine fetal death increases.

Risk factors for Rhesus conflict

Divided into: 1. Pregnancy-related: - any type of termination of pregnancy: miscarriage, instrumental and medical abortions; - ectopic pregnancy; - childbirth, namely, in the third period, when the placenta separates from the wall of the uterus; - complication of pregnancy or childbirth - premature placental abruption, which is accompanied by bleeding from the vessels of the placenta; - any invasive research methods: (amniocentesis, cordocentesis - puncture of the amniotic sac or umbilical cord). 2. Unrelated to pregnancy: - immunization during blood transfusion; - using one needle for intravenous drug use.

Symptoms of Rh conflict

The patient has no clinical manifestations, her condition does not suffer.

Symptoms of hemolytic disease in the fetus during pregnancy can only be detected by ultrasound examination, they are: swelling, accumulation of fluid in the cavities (abdominal, thoracic, in the cavity of the pericardial sac); due to the accumulation of fluid in the abdominal cavity of the fetus, the size of the tummy increases, the fetus takes a certain position “Buddha pose” (when, unlike the norm, the limbs are removed from the enlarged tummy), an increase in the size of the liver and spleen, an increase in the size of the heart, a “double” contour appears heads (as a result of swelling of the soft tissues of the head). Also, swelling is determined and, accordingly, thickening of the placenta and an increase in the diameter of the umbilical cord vein. Depending on the predominance of one or another symptom, three forms of hemolytic disease of the fetus are distinguished: edematous, icteric and anemic.

Diagnosis of Rh conflict and pregnancy management tactics

The purpose of monitoring pregnant women during Rh immunization is: examination to identify sensitization, prophylaxis of Rh immunization, early diagnosis of hemolytic disease of the fetus and its correction, as well as determining the most optimal timing for delivery. When registering for pregnancy, it is necessary to determine the blood type of both the pregnant woman herself and the father of the child in a planned manner. If the mother has Rh-negative blood and the father has Rh-positive blood, pregnant women undergo a blood test for antibodies once a month, monitoring the dynamics of the antibody titer. In the presence of any antibody titer, the pregnancy is considered Rhesus sensitized. If antibodies are detected for the first time, their class is determined (IgM or IgG). Next, a blood test for antibodies is carried out monthly, observing the patient up to 20 weeks in the antenatal clinic, and after 20 weeks, they are sent to specialized centers to determine further management tactics, possibly carry out treatment and decide on the method and timing of delivery.

Starting from 18 weeks, the fetal condition is assessed using ultrasound.

Methods for assessing the condition of the fetus are divided into:

1. Non-invasive methods. — Ultrasound, which evaluates: the size of the fetal organs, the presence of free fluid in the cavities, the presence of swelling, the thickness of the placenta and the diameter of the umbilical cord vein. The first ultrasound is performed at 18-20 weeks, repeated at 24-26 weeks, 30-32 weeks, 34-36 and immediately before delivery. Depending on the severity of the fetal condition, this study may be performed more frequently, even daily (as, for example, after a blood transfusion to the fetus). - Doppler ultrasound, which evaluates the functional parameters of the heart, the speed of blood flow in the large vessels of the fetus and the umbilical cord, etc. — cardiotocography evaluates the reactivity of the fetal cardiovascular system, detects the presence or absence of hypoxia (lack of oxygen).

2. Invasive: - amniocentesis - puncture of the membranes for the purpose of collecting amniotic fluid to assess the severity of hemolysis by the content of bilirubin (a breakdown product of hemoglobin), which is one of the most accurate methods for assessing the severity of the fetal condition. Unfortunately, this method is fraught with many complications: infection, prenatal rupture of amniotic fluid, premature birth, bleeding, premature placental abruption. Indications for amniocentesis: antibody titer 1:16 or more, the patient has children who have suffered a severe form of hemolytic disease of the newborn. - cordocentesis - puncture of the umbilical cord to collect blood. The method allows you to accurately assess the severity of hemolysis and simultaneously perform an intrauterine blood transfusion to the fetus. In addition to those complications that are typical for amniocentesis, during cordocentesis it is also possible to develop an umbilical cord hematoma and bleeding from the puncture site. Indications for cordocentesis are the determination of signs of hemolytic disease of the fetus by ultrasound, antibody titer 1:32 or higher, the presence of children in the patient who have suffered severe a form of HDP in the past or those who died from it, a high level of bilirubin in the amniotic fluid obtained during amniocentesis.

Due to the possible risk, before performing either procedure, the patient must be informed by the doctor about the possibility of adverse consequences of the procedure and give her written consent to it.

Treatment of Rhesus conflict

In modern obstetrics, the only treatment method with proven effectiveness is intrauterine blood transfusion, which is performed for severe anemia (anemia) in the fetus. This type of treatment is carried out only in a hospital and can achieve a significant improvement in the condition of the fetus and reduce the risk of premature birth and the development of a severe form of the disease after birth.

Patients of a high risk group (whose antibody titer is detected in the early stages, those who have an antibody titer of 1:16 or higher, those whose previous pregnancy proceeded with Rhesus conflict) are observed in a antenatal clinic for up to 20 weeks, and then referred to specialized hospitals for the above treatment.

Various methods of purifying the mother's blood from antibodies (plasmapheresis, hemosorption), methods affecting the activity of the immune system (desensitizing therapy, immunoglobulin therapy, transplanting a skin flap from the child's father to the patient) are currently considered ineffective or even ineffective.

But, unfortunately, despite significant advances in the field of correcting the condition of the fetus, the most effective way is to stop the flow of maternal antibodies to it, which can only be achieved by delivery.

Delivery in case of Rhesus conflict

Unfortunately, with Rh sensitization, it is often necessary to deliver early, because in late pregnancy there is an increase in the number of antibodies that reach the fetus. Depending on the condition of the fetus and the duration of pregnancy, the method of delivery is individual in each individual case. It is believed that a caesarean section is more gentle on the fetus, and therefore in severe cases it is resorted to. If the condition of the fetus is satisfactory, the gestation period is over 36 weeks, in a multiparous woman it is possible to conduct labor through the natural birth canal with careful monitoring of the condition of the fetus and prevention of intrauterine hypoxia. If his condition worsens during labor, the management plan may be revised in favor of a cesarean section.

Prognosis for Rhesus conflict

The prognosis depends on how early Rhesus immunization was diagnosed, on the magnitude of the antibody titer and the rate of its increase, as well as on the form of hemolytic disease of the fetus. The earlier antibodies are detected in the mother’s blood, for example, at 8-10 weeks, the more prognostically unfavorable it is. A rapid increase in antibody titer, a titer above 1:16, and its early detection (less than 20 weeks) is the basis for an unfavorable prognosis. In such cases, not only the risk of hemolytic disease of the fetus increases, but also the risk of miscarriage.

The most prognostically unfavorable form of hemolytic disease of the fetus is edematous. Such children often require treatment in a pediatric intensive care unit and replacement blood transfusion. The most prognostically favorable form is the anemic form (depending on the severity of anemia). In the icteric form, the determining criterion is the level of bilirubin. The higher it is, the higher the possibility of damage to the central nervous system of the fetus, which later manifests itself as dementia and hearing loss.